Natural sapphires carry within them clear signs of slow crystallization. Some of the external elements sometimes remain preserved in the gem which helps its identification. Like all other precious gems it should have inclusions which should be visible to the naked eye or under magnification. Otherwise, it is a piece of glass or a synthetic substance.
The inclusions are generally like ‘feathers’ or are like finger print impressions. Liquid inclusions looking like lace are also sometimes visible.
Synthetic sapphires are very common in the market and many traders in order to earn fast money sell them as originals. These are very clear and under magnification show bubble like inclusions. Sometimes feather like inclusions have also seen but they shine abnormally under light.